Catapres

WARNINGS

Withdrawal

Patients should be instructed not to discontinue therapy without consulting
their physician. Sudden cessation of clonidine treatment has, in some cases,
resulted in symptoms such as nervousness, agitation, headache, and tremor accompanied
or followed by a rapid rise in blood pressure and elevated catecholamine concentrations
in the plasma. The likelihood of such reactions to discontinuation of clonidine
therapy appears to be greater after administration of higher doses or continuation
of concomitant beta-blocker treatment and special caution is therefore advised
in these situations. Rare instances of hypertensive encephalopathy, cerebrovascular
accidents and death have been reported after clonidine withdrawal. When discontinuing
therapy with Catapres (clonidine hydrochloride, USP) tablets, the physician
should reduce the dose gradually over 2 to 4 days to avoid withdrawal symptomatology.

An excessive rise in blood pressure following discontinuation of Catapres (clonidine) tablets
therapy can be reversed by administration of oral clonidine hydrochloride or
by intravenous phentolamine. If therapy is to be discontinued in patients receiving
a beta-blocker and clonidine concurrently, the beta-blocker should be withdrawn
several days before the gradual discontinuation of Catapres (clonidine) tablets.

Because children commonly have gastrointestinal illnesses that lead to vomiting,
they may be particularly susceptible to hypertensive episodes resulting from
abrupt inability to take medication.

PRECAUTIONS

General

In patients who have developed localized contact sensitization to Catapres-TTS
(clonidine), continuation of Catapres-TTS or substitution of oral clonidine
hydrochloride therapy may be associated with the development of a generalized
skin rash.

In patients who develop an allergic reaction to Catapres-TTS, substitution
of oral clonidine hydrochloride may also elicit an allergic reaction (including
generalized rash, urticaria, or angioedema).

Perioperative Use

Administration of Catapres (clonidine) tablets should be continued to within four hours
of surgery and resumed as soon as possible thereafter. Blood pressure should
be carefully monitored during surgery and additional measures to control blood
pressure should be available if required.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Chronic dietary administration of clonidine was not carcinogenic to rats (132
weeks) or mice (78 weeks) dosed, respectively, at up to 46 or 70 times the maximum
recommended daily human dose as mg/kg (9 or 6 times the MRDHD on a mg/m basis).
There was no evidence of genotoxicity in the Ames test for mutagenicity or mouse
micronucleus test for clastogenicity.

Fertility of male or female rats was unaffected by clonidine doses as high
as 150 mcg/kg (approximately 3 times MRDHD). In a separate experiment, fertility
of female rats appeared to be affected at dose levels of 500 to 2000 mcg/kg
(10 to 40 times the oral MRDHD on a mg/kg basis; 2 to 8 times the MRDHD on a
mg/m basis).

Pregnancy

Teratogenic Effects - Pregnancy Category C.

Reproduction studies performed in rabbits at doses up to approximately 3 times
the oral maximum recommended daily human dose (MRDHD) of Catapres (clonidine
hydrochloride, USP) tablets produced no evidence of a teratogenic or embryotoxic
potential in rabbits. In rats, however, doses as low as 1/3 the oral MRDHD (1/15
the MRDHD on a mg/m basis) of clonidine were associated with increased resorptions
in a study in which dams were treated continuously from 2 months prior to mating.
Increased resorptions were not associated with treatment at the same time or
at higher dose levels (up to 3 times the oral MRDHD) when the dams were treated
on gestation days 6-15. Increases in resorption were observed at much higher
dose levels (40 times the oral MRDHD on a mg/kg basis; 4 to 8 times the MRDHD
on a mg/m basis) in mice and rats treated on gestation days 1-14 (lowest dose
employed in the study was 500 mcg/kg).

No adequate, well-controlled studies have been conducted in pregnant women.
Because animal reproduction studies are not always predictive of human response,
this drug should be used during pregnancy only if clearly needed.

Nursing Mothers

As clonidine hydrochloride is excreted in human milk, caution should be exercised
when Catapres (clonidine hydrochloride, USP) tablets are administered to a nursing
woman.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established in
adequate and well-controlled trials (see WARNINGS, Withdrawal).

Last reviewed on RxList: 1/24/2011
This monograph has been modified to include the generic and brand name in many instances.